1. Field of the Invention
The present invention relates to a coating composition to provide a coated layer having excellent mar resistance and transparency. More particularly, it relates to a coating composition used for improving mar resistance of a transparent plastic product.
2. Description of the Prior Arts
In usual, plastic products such as products of polycarbonate, polymethyl, methacrylate, polyestyrene, polyvinyl chloride and ABS resin have been used in various field because of excellent light weight, processability and impact strength etc. The surface hardnesses of the plastic products are relatively whereby the surface is easily damaged or the appearance is deteriorated or the transparency of the product is easily lost. Thus, the plastic products could not be used in certain fields requiring high transparency and mar resistance, such as lense for eye glass, headlight lense for cars and organic glass for car windows, etc.
Certain coating compositions for improving surface hardness of plastic products have been known. For example, organic materials such as melamine resin and high hardness acryl resins, inorganic materials such as silica coated by an evaporation and organic-inorganic material such as polyalkyl siloxane obtained by hydrolysis of an organic silane. Some of the organic materials have desired hardness measured by forcibly falling sand, however the organic materials have not desired hardness measured an emery paper test or an eraser rubber test. On the other hand, the inorganic materials and the organic-inorganic materials have relatively high hardness, however, costs for the materials and the coatings are relatively high.